BIOC 384 EXAM 3 ALL QUESTIONS WITH VERIFIED
ANSWERS
Module 7
Acetylcholinesterase is an important enzyme in the nervous system.
Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a
covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n)
irreversible inhibitor.
competitive inhibitor.
reversible inhibitor.
allosteric effector. - Answers - irreversible inhibitor.
"forms a covalent bond with a Ser"
An inhibitor that binds only to the ES complex and not free enzyme is known as a(n)
___________ inhibitor.
competitive
uncompetitive
irreversible
mixed - Answers - uncompetitive
An enzyme undergoes a mutation that causes it to lose the ability to be regulated via
phosphorylation. Which of the following mutations may lead to this loss of regulation?
Assume that the overall structure is not altered by the mutation.
Tyr --> Phe
Thr --> Ser
Ser --> Tyr
Ser --> Thr - Answers - Tyr --> Phe
Put the following steps in the correct order describing inhibition of glutamine synthetase
by a metabolite allosteric effector.
, A. Adenylation of glutamine synthetase.
B. Glutamine binding to uridylyltransferase
C. Deuridylation of glutamine synthetase adenylyltransferase
B, C, A
B, A, C
C, B, A
A, B, C - Answers - B, C, A
B. Glutamine binding to uridylyltransferase
C. Deuridylation of glutamine synthetase adenylyltransferase
A. Adenylation of glutamine synthetase.
Put the following signal transduction pathway steps in the correct order:
upstream signaling protein
second messenger
receptor protein
first messenger
target proteins
downstream signaling protein
D, C, A, B, F, E
C, D, A, B, F, E
D, C, B, A, F, E
D, E, C, A, B, F - Answers - D, C, A, B, F, E
first messenger
receptor protein
upstream signaling protein
second messenger
downstream signaling protein
target proteins
Muscle relaxation in response to neuronal stimulation and nitric oxide signaling would
be reduced if a(n) ______________was present.
inhibitor of protein kinase A
stimulator of cGMP phosphodiesterase
stimulator of guanylate cyclase
inhibitor of acetylcholine esterase - Answers - stimulator of cGMP phosphodiesterase
The GS-alpha subunit of trimeric G proteins can function to
ANSWERS
Module 7
Acetylcholinesterase is an important enzyme in the nervous system.
Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a
covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n)
irreversible inhibitor.
competitive inhibitor.
reversible inhibitor.
allosteric effector. - Answers - irreversible inhibitor.
"forms a covalent bond with a Ser"
An inhibitor that binds only to the ES complex and not free enzyme is known as a(n)
___________ inhibitor.
competitive
uncompetitive
irreversible
mixed - Answers - uncompetitive
An enzyme undergoes a mutation that causes it to lose the ability to be regulated via
phosphorylation. Which of the following mutations may lead to this loss of regulation?
Assume that the overall structure is not altered by the mutation.
Tyr --> Phe
Thr --> Ser
Ser --> Tyr
Ser --> Thr - Answers - Tyr --> Phe
Put the following steps in the correct order describing inhibition of glutamine synthetase
by a metabolite allosteric effector.
, A. Adenylation of glutamine synthetase.
B. Glutamine binding to uridylyltransferase
C. Deuridylation of glutamine synthetase adenylyltransferase
B, C, A
B, A, C
C, B, A
A, B, C - Answers - B, C, A
B. Glutamine binding to uridylyltransferase
C. Deuridylation of glutamine synthetase adenylyltransferase
A. Adenylation of glutamine synthetase.
Put the following signal transduction pathway steps in the correct order:
upstream signaling protein
second messenger
receptor protein
first messenger
target proteins
downstream signaling protein
D, C, A, B, F, E
C, D, A, B, F, E
D, C, B, A, F, E
D, E, C, A, B, F - Answers - D, C, A, B, F, E
first messenger
receptor protein
upstream signaling protein
second messenger
downstream signaling protein
target proteins
Muscle relaxation in response to neuronal stimulation and nitric oxide signaling would
be reduced if a(n) ______________was present.
inhibitor of protein kinase A
stimulator of cGMP phosphodiesterase
stimulator of guanylate cyclase
inhibitor of acetylcholine esterase - Answers - stimulator of cGMP phosphodiesterase
The GS-alpha subunit of trimeric G proteins can function to
